1. Field of the Invention
This invention relates to devices for applying fluid to biological tissue and more particularly to apparatus which instills an aqueous solution to the surface of the eyeballs. The invention introduces artificial tear fluid to relieve the discomfort and potential ocular damage caused by chronic dry-eye condition, which is especially uncomfortable in elderly people. The invention also provides a corresponding method to treat eye dryness.
Many people suffer from a lack of eye moisture. Even though artificial tear solutions increase eye moisture and relieve discomfort, the application of such artificial tear solutions provides only temporary relief and therefore dry-eye sufferers commonly apply artificial tear solution to their eyes several times within the course of a day. The burden and interruption caused by frequent applications of eye drops is not conducive to maintain a proper moisture level and to apply the required dosages.
The present invention also finds use in applying an active medicinal agent dissolved in a volume of fluid administered to the eye. Fluids with active medical ingredients require careful control of the quantity of fluid administered. It generally is difficult, with manual application of the fluid using an eyedropper, to control the number of drops introduced to the eye.
Some eyedroppers exist with a fluid chamber having a threaded piston that screws within a correspondingly threaded cylinder. When the piston is advanced within the cylinder and held in a particular position, a predetermined volume of fluid is expelled from the chamber. However, due to the complicated structure of these devices, their bulkiness make them more cumbersome than typical eyedroppers.
Other devices have been developed to deliver fluid to an eyeball. These devices typically work by pumping fluid from a reservoir through a tube that has a distal end positioned adjacent to the eye. In some instances, the tube is surgically implanted under the skin. It begins at a fluid reservoir positioned, for example, at the lumbar region and ends adjacent the eye. These devices are cumbersome and invasive and the mechanism needed to pump the fluid through the tube is bulky and requires a heavy and bulky power source. Furthermore, control problems result from having to pump fluid to the eye through a relatively lengthy tube. Furthermore, fluid flow can easily be disrupted by patient movement and by inadvertent pinching or collapsing of the delivery tube.
In summary, the prior art has been characterized by apparatus that applies fluid droplets at a rapid and nonuniform localized flow so that such treatment/characteristic of the prior art causes non-uniform flooding on the exposed eyeball with damage to the eyeball resulting from the rapid, non-uniform application of moisture to the dry eyeball requiring treatment.
2. State of the Prior Art
U.S. Pat. No. 2,527,947 to Loos, issued Oct. 31, 1950, discloses a laminated eye protector comprising a flexible multiple ply pad consisting of an outer layer of relatively thick fabric which is relatively impervious to sun rays and moisture and is heat absorptive, an intermediate layer of absorbent material and an inner layer of relatively loosely woven fabric. The inner layer is porous to permit medication or water in the intermediate layer to travel through the inner layer to the eyeball surface. This patented device does not evaporate eye protecting moisture into a chamber immediately outside and surrounding the eyeball.
U.S. Pat. No. 3,826,258 to Abraham, issued Jul. 30, 1974, shows eye treatment apparatus that comprises a very small number of gradually released medicine carriers in a saline or antiseptic solution. The invention defined in this patent discloses a prepackaged ampoule-like dropper and does not provide means for evaporating an eye treating fluid within a chamber formed between an eyeglass frame on one hand and the eye and cheek of a user on the other hand.
U.S. Pat. No. 3,902,486 to Guichard, issued Sep. 2, 1975, relates to a portable nasal diffuser and is mentioned because this patent was reported in a novelty search. It would not be obvious to use a portable nasal diffuser to apply moisture to a dry eyeball surface.
U.S. Pat. No. 4,573,982 to Forbes, et al., issued Mar. 4, 1986, discloses an eyeglass frame constructed and arranged to apply a unit dose ophthalmic drug in liquid form. The liquid is applied directly to the eye as discrete droplets that treat the eyeball surface non-uniformly. A portion of the eyeball so treated remains dry after such treatment so that the dry eyeball problem is not fully corrected.
U.S. Pat. No. 4,908,024 to Py, issued Mar. 13, 1990, discloses an ocular treatment apparatus that is formed by a frame worn by a patient to support one or two light-deviation apparatus. The patient rotates his eyes upward and the light-deviation apparatus permits him to observe the lower ocular area to apply ocular treatment material in a location normally not seen by the wearer.
U.S. Pat. No. 5,171,306 to Vo, issued Dec. 15, 1992, discloses an eye drop delivery system for administering eye drops to at least one eye of a user and comprises a fluid reservoir for holding a supply of eye drop fluid, a tube for conducting eye drop fluid from the fluid reservoir to at least one eye of the user and fluid driving apparatus for continuously urging eye drop fluid from the fluid reservoir to at least one distal end of the tube and fluid control apparatus for successfully permitting eye drop fluid to flow freely from the tube. The fluid control means causes individual drops of eye drop fluid to be applied to the eye of the wearer.
U.S. Pat. No. 5,368,582 to Batera, issued Nov. 29, 1994, discloses a spectacle-like device that mounts a system of pump elements that can project droplets of liquid onto a wearer's eye. The use of pump elements complicates the structure of the device and does not suggest the slow, uniform application of evaporated fluid into a chamber adjacent to and surrounding the eyeballs.